How to Fix a TGraphTask Reading Stale Data from a Missing Dependency in Unreal

You split work into two TGraphTasks where the second reads what the first wrote, but the result is sometimes garbage. Without a declared prerequisite, the graph runs them in parallel. Here is how to enforce the dependency.

How to fix it

1. Capture the producer's completion event

When creating the producer with TGraphTask<...>::CreateTask(), keep its returned FGraphEventRef so you can depend on it.

2. List it as a prerequisite

Create the consumer with the producer event in its prerequisites: TGraphTask<...>::CreateTask(&Prereqs), so the graph waits for the producer to complete first.

3. Wait on the final event

If the game thread needs the result, call FTaskGraphInterface::Get().WaitUntilTaskCompletes(FinalEvent) or use a completion callback rather than assuming a fixed ordering.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unreal Engine error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.